EP3869082A1 - High pressure vessel - Google Patents

Abstract

A high-pressure container comprising a cylinder (10) as a central part, the cylinder (10) consisting of a multilayer composite plastic (11) comprising a barrier layer (12), the high-pressure container also having at least one half-shell (13) at one axial end of the cylinder (10), wherein the half-shell (13) consists of a multilayer composite plastic (11) which comprises a barrier layer (12), the half-shell (13) further comprising an essentially rotationally symmetrical insert part (1), namely a boss part, wherein the insert (1) comprises an undercut with respect to a demolding in the direction of the longitudinal center axis of the insert (1), the multi-layer composite plastic (11) of the half-shell (13) being arranged axially on both sides of the undercut of the insert (1) .

Description

Field of invention

The present invention relates to a high-pressure container, in particular for storing a fuel for a motor vehicle.

State of the art

It is known that high-pressure containers, for example for storing hydrogen as fuel for motor vehicles, can be built up from an inner layer, the so-called "liner", and a winding of fiber material around the liner.

To manufacture a container, it is known to use the technologies of blow molding and thermoforming. The production is then based on the reshaping of tubular or plate-shaped semi-finished products. These are brought into their final form by negative pressure and / or overpressure. For example, two half-shells can be produced that are joined together to form a container.

There are two common production methods for the application of gas-tight liners for type IV containers, which are used to store gases under pressure. On the one hand the blow molding of entire liners, on the other hand the method of manufacturing segments of the container in injection molding and extrusion processes as well as a downstream connection of these components by a joining process.

The materials used here are mostly based on HDPE (high density polyethylene) or polyamides.

An important distinguishing feature for liner materials are the mechanical low-temperature properties and the emission properties. Monolayer materials such as polyamide have good barrier properties for gases, but not optimal low-temperature properties. HDPE, on the other hand, does not have a suitable barrier effect, but has very good low-temperature properties.

For this reason, polyamide is currently mainly used for applications in the hydrogen sector. However, this sets limits in terms of component size, especially for blow molding technology. The available suitable types are also expensive due to their complex additives and problematic when used at low temperatures.

High-pressure containers for gases are subject to large temperature fluctuations in the course of their operation (filling, storage and emptying). This places high demands on the materials and, in particular, on the liner.

In connection with the lightweight construction and the use of composite materials, the challenge in this context is to connect the different materials to one another in a gas-tight manner at the joint.

Summary of the invention

It is an object of the invention to improve a high-pressure container in this regard and, in particular, to specify a high-pressure container which also meets the requirements for tightness and permeation for a high-pressure container in a transition area to a boss part and is easy and inexpensive to manufacture.

The object is achieved by a high-pressure container comprising a cylinder as a central part, the cylinder consisting of a multilayer composite plastic which comprises a barrier layer, the high-pressure container further comprising at least one half-shell at one axial end of the cylinder, the half-shell being made from a multilayer composite There is plastic which comprises a barrier layer, the half-shell further comprising an essentially rotationally symmetrical insert part, namely a boss part, the insert part comprising an undercut with respect to a demolding in the direction of the longitudinal center axis of the insert part, the multi-layer composite plastic axially on the half-shell is arranged on both sides of the undercut of the insert.

An "undercut in relation to a demolding in the direction of the longitudinal center axis of the insert" means that the insert has a formation that is further away from the longitudinal center axis of the insert than areas of the insert that are axially before and after this formation, so that a Removing the insert from the plastic before and after this formation or this undercut is problematic per se. The formation or undercut can in particular have a larger diameter than areas of the insert before and after the undercut.

According to the invention, a multilayer composite is used as the material for the liner, both in the central part formed by the cylinder and in at least one, preferably in both axial end regions of the container. Such multi-layer plastics can be formed into a half-shell in a simple manner by means of blow molding or deep drawing or vacuum molding. The cylinder in the middle part can, for example, also be blow molded or, for example, extruded. According to the invention, a boss part is used which has an undercut with regard to demolding in the direction of the longitudinal center axis of the insert part. Such an undercut is present when the insert is made wider in one area of its axial extent than in an area behind it, which is also filled with plastic. According to the invention, the multilayer composite plastic is arranged on both sides of the undercut, axially in front of and behind the undercut. The usually metallic boss part is thus embedded in the plastic that has the barrier layer. The high-pressure container thus has good permeation properties also in the area of the transition to the Bos part. The production of the half-shell with embedded boss part and the entire high-pressure container is nevertheless possible in a cost-effective manner, since, as will be described in more detail later, the introduction of the plastic is possible despite undercutting by means of blow molding or vacuum deep drawing.

The undercut is preferably formed by a foot part on the end of the insert part facing the interior of the container, which has a larger diameter than a central part of the insert part.

The foot part preferably has at least one groove which is filled with the multi-layer composite plastic of the half-shell, preferably several Grooves. The presence of the plastic in the grooves can improve the form fit between the boss part and the plastic of the liner.

The foot part preferably essentially forms a hollow cone or hollow cylinder.

Particularly preferably, at least one groove filled with the multi-layer composite plastic of the half-shell runs around an inner circumference of the foot part.

The multilayer composite plastic of the cylinder preferably merges into the multilayer composite plastic of the half-shell. The barrier layer preferably runs as continuously as possible at the transition between the cylinder and the half-shell.

The multilayer composite plastic of the half-shell, and preferably also the multilayer composite plastic of the cylinder, preferably comprises at least one layer of HDPE and a barrier layer, in particular EVOH, preferably also a regranulate, i.e. a Regrind layer, and / or a second HDPE layer and / or at least one adhesion promoter layer.

The high-pressure container preferably comprises two half-shells at the axial ends of the cylinder, both half-shells preferably being designed as described above for the first half-shell.

The cylinder and the two half-shells are preferably wrapped with a fiber material, preferably with a composite material comprising carbon fibers and / or glass fibers and / or epoxy resin.

• eine vorgeheizte erste Kunststoffplatte wird auf die erste Werkzeughälfte gelegt,
• die erste Kunststoffplatte wird mittels Unterdruck oder Druck an die erste Werkzeughälfte gesaugt oder gepresst,
• hierdurch wird der Kunststoff der ersten Kunststoffplatte bereichsweise hinter einer Hinterschneidung eines Einlegeteils, nämlich des Bossteils, seitlich beabstandet vom Einlegeteil angeordnet, oder das Einlegeteil wird, nach dem Saugen oder Pressen der ersten Kunststoffplatte an die erste Werkzeughälfte, so positioniert, dass Kunststoff der ersten Kunststoffplatte bereichsweise hinter einer Hinterschneidung des Einlegeteils seitlich beabstandet vom Einlegeteil angeordnet ist,
• danach wird mittels eines Schiebers oder eines Unterdrucks oder eines Drucks der Kunststoff der ersten Kunststoffplatte hinter der Hinterschneidung von seitlich beabstandet des Einlegeteils an das Einlegeteil gedrückt oder gesaugt, so dass ein Raum hinter der Hinterschneidung des Einlegeteils mit dem Kunststoff gefüllt wird.

A high-pressure container according to the invention can preferably be produced with a tool, with a first tool half that forms a die, and the steps include:

• a preheated first plastic plate is placed on the first mold half,
• the first plastic plate is sucked or pressed onto the first mold half by means of negative pressure or pressure,
• As a result, the plastic of the first plastic plate is partially arranged behind an undercut of an insert, namely the boss part, laterally spaced from the insert, or the insert is positioned, after sucking or pressing the first plastic plate against the first tool half, so that the plastic of the first plastic plate is arranged in some areas behind an undercut of the insert, laterally spaced from the insert,
• thereafter, the plastic of the first plastic plate behind the undercut is pressed or sucked against the insert from laterally spaced from the insert by means of a slider or a negative pressure or a pressure, so that a space behind the undercut of the insert is filled with the plastic.

The boss part is thus preferably inserted into the tool as an insert part and enclosed in a blow molding or deep-drawing process with the plastic plate, in particular a permeation-tight multilayer composite, so that the plastic also gets into areas behind an undercut. For this purpose, a plastic plate is first sucked or pressed onto the first tool half by means of negative pressure or pressure. In this case, the insert can already be positioned in such a way that, by sucking or pressing the plastic onto the first tool half, the plastic of the first plastic plate is partially behind an undercut of the insert, laterally spaced from the insert, is arranged.

Alternatively, the insert can only be positioned after the plastic has been sucked or pressed onto the first tool half in such a way that the plastic of the first plastic plate is arranged laterally at a distance from the insert behind the undercut, for example by sliding the insert or the insert into the first Tool half is introduced.

Then the plastic of the first plastic plate is pressed or sucked from the side of the insert to the insert by means of a slide or a vacuum or a pressure, so that a space behind the undercut of the insert is filled with the plastic previously located on the side and a form fit is created.

As a result, despite simple production by means of blow molding or vacuum molding, the plastic also reaches areas behind the insert and the result is an improved sealing effect of the plastic, in particular the multilayer composite, towards the insert, in particular the metallic boss part. To achieve inclusion in the plastic, slides and / or a vacuum or compressed air are used.

“Laterally spaced” here means essentially at a distance from a longitudinal center axis of the insert, which can preferably also coincide with the longitudinal center axis of the pressure vessel. The plastic can initially run essentially parallel to the longitudinal center axis of the insert and preferably also to the surrounding container wall. The plastic will then be essentially normal to the longitudinal center axis of the insert, in particular radially inwards on all sides, towards the insert, sucked, blown or pushed.

The fact that the plastic is sucked or pressed towards the insert takes place after the insert has been positioned, so that the plastic is laterally spaced from the insert in some areas, can also take place in a continuous process, so that the insert is moved and positioned further and in doing so, new plastic is sucked in or pressed in each time, so that the positioning of the insert and the sucking in or pressing of the plastic behind the undercut take place virtually simultaneously.

The resulting half-shell can be connected to a second half-shell or an extruded or blow-molded multi-layer cylinder in a further process step. This forms the core and thus the basis for a further winding process in which the container can obtain its mechanical strength through a composite material made of carbon and / or glass and epoxy resin.

The tool preferably comprises a second tool half which forms a punch, the second tool half being moved onto the first tool half in order to form the inner contour of the half-shell. For this purpose, the second tool half can form the shape of the first plastic plate inside the half-shell. Instead, the second tool half can also be equipped with a second plastic plate that forms the inner contour of the half-shell.

Preferably, after the first plastic plate has been sucked or pressed against the first tool half, the insert is raised in relation to the first tool half in order to position the insert so that Plastic of the first plastic plate is arranged behind the undercut laterally spaced from the insert. The lifting can be done with the help of a movable receptacle for the insert. The insert can be arranged on the outside of the container on the first plastic plate and the lifting can thus take place along the longitudinal center axis of the insert and preferably also along the longitudinal center axis of the high-pressure container, in particular towards the later center of the container.

Preferably, after the space behind the undercut of the insert with the plastic has been filled, the insert is lowered again in relation to the first tool half. Particularly preferably, the lowering takes place simultaneously with the movement of the second tool half onto the first tool half.

According to another embodiment, the insert is only placed on the first plastic plate after the first plastic plate has been sucked or pressed against the first tool half in order to position the insert so that the plastic of the first plastic plate is arranged laterally spaced from the insert behind the undercut. The insert can thus be arranged on the inside of the container on the first plastic plate. A second plastic plate can in turn be arranged on the inside of the insert part of the container.

The plastic of the first plastic plate can be cut off axially behind the plastic-filled space behind the undercut, so that there is no more plastic behind the undercut, in particular on the outside of the undercut on the container.

A preheated second plastic plate is preferably placed on the second tool half, then the second plastic plate is sucked or pressed onto the second tool half by means of negative pressure or pressure, and the second tool half with the second plastic plate is moved onto the first tool half in order to form the inner contour of the half-shell.

The first plastic plate is preferably a multilayer composite, the multilayer composite preferably comprising a layer made of HDPE (high density polyethylene) and a barrier layer, in particular EVOH (ethylene vinyl alcohol copolymer). The multilayer composite particularly preferably also comprises a regranulate material or regranulate and / or one or more adhesion promoter layers. HDPE preferably forms the outermost layer of the multilayer composite and can also form the innermost layer.

A method for producing a high-pressure container preferably comprises that a half-shell is produced by a method as described above, the half-shell with a further half-shell - which, for example, can also include an insert and which can be produced in the same manner described above - or with at least one - preferably extruded or blow molded - cylinder and an end cap is connected to form a closed container.

The closed container is preferably wrapped with a fiber material, preferably with a composite material comprising carbon fibers and / or glass fibers and / or epoxy resin.

Brief description of the drawings

Fig. 1 - Fig. 6

sind Schnittansichten die Schritte eines Verfahrens zur Herstellung einer Halbschale für einen erfindungsgemäßen Hochdruckbehälter in einer ersten Ausführungsform zeigen.

Fig. 7

ist eine Detaildarstellung der Fig. 3 im Bereich um die Hinterschneidung des Einlegeteils 1.

Fig. 8

ist eine Detaildarstellung der Fig. 4 im Bereich um die Hinterschneidung des Einlegeteils 1.

Fig. 9 - Fig. 14

sind Schnittansichten die Schritte eines Verfahrens zur Herstellung einer Halbschale für einen erfindungsgemäßen Hochdruckbehälter in einer zweiten Ausführungsform zeigen.

Fig. 15

ist eine Schnittansicht eines erfindungsgemäßen Hochdruckbehälters.

The invention is described below by way of example with reference to the drawings.

Figures 1-6

are sectional views showing the steps of a method for producing a half-shell for a high-pressure container according to the invention in a first embodiment.

Fig. 7

is a detailed representation of the Fig. 3 in the area around the undercut of the insert 1.

Fig. 8

is a detailed representation of the Fig. 4 in the area around the undercut of the insert 1.

Figures 9-14

are sectional views showing the steps of a method for producing a half-shell for a high-pressure container according to the invention in a second embodiment.

Fig. 15

Fig. 3 is a sectional view of a high pressure container according to the invention.

Detailed description of the invention

In the Fig. 1-6 shows a method for producing a half-shell for a high-pressure container according to the invention.

A tool is used with a first tool half 2, which forms a die, and with a second tool half 5, which forms a punch.

The tool thus consists of two tool halves, the insert part being positioned on a movable receptacle 7 in the first tool half 2, preferably the lower tool half. The second tool half 5, preferably the upper tool half, functions as a stamp in order to apply a compression at the end of the process. In addition, the second tool half 5 can also be equipped with a second insert. With the aid of slides 4 and / or a vacuum provided in the tool, the plastic is brought to the points required for the form fit.

For this purpose, a preheated first plastic plate 3 is placed on the first tool half 2 and the first plastic plate 3 is sucked or pressed onto the first tool half 2 by means of negative pressure or pressure. The insert part 1, that is to say the boss part, is then positioned in such a way that the plastic of the first plastic plate 3 is arranged in some areas behind an undercut, laterally spaced from the insert part 1. Alternatively, it is also possible to dispense with moving the insert 1, so that the plastic immediately falls on a correctly positioned insert 1, accordingly Fig. 3 , is sucked.

Then the plastic of the first plastic plate 3 behind the undercut from laterally spaced from the insert 1 is pressed or sucked against the insert 1 by means of a slide 4 or a vacuum or a pressure, so that a space behind the undercut of the insert 1 is filled with the plastic .

Finally, the second tool half 5 is moved onto the first tool half 2 in order to form the inner contour of the half-shell.

That in the Figures 1 to 6 The singlesheet procedure shows the following steps in detail:
In the first step of the single sheet process ( Fig. 1 ) one tool half, namely the first tool half 2, is equipped with the insert 1 - namely a boss part - and a preheated plastic plate 3. The insert 1 is in the starting position.

Optionally, the second tool half 5 can also be equipped with a further insert at this point. The plastic plate 3 is sucked into the first tool half 2, which depicts the outer component geometry, with the aid of a vacuum.

In order to fill the space behind the undercut of the insert 1, which is necessary for the form fit, with plastic, the insert 1 is positioned in the first tool half 2 on a movable receptacle 7. By lifting the component and, for example, using a vacuum and / or slides 4 at the same time, the space behind the undercut of the component is filled - FIGS. 3 and 4 .

In the next step ( Fig. 5 ) the second tool half 5 is lowered onto the first tool half 2 with a defined clamping force and the inner contour of the component is mapped. In the course of this process step, the insert 1 can optionally be brought back into the starting position. As a result, the plastic behind the undercuts is additionally pressed and the form fit between the insert 1 and the plastic of the first plastic plate 3 is increased.

An alternative embodiment of the manufacturing process is shown in FIG FIGS. 9 to 14 , namely a twin sheet process for producing the half-shell.

In the first step of the twin sheet process, both mold halves 2, 5 are each equipped with a preheated plastic plate 3, 6 ( Fig. 9 ). Optionally, the second tool half 5 can also be equipped with an insert at this point. The plastic plates 3, 6 are sucked into or onto the respective tool halves 2, 5 with the aid of a vacuum, which depict the outer and inner component geometry ( Fig. 10 ).

In the next step, the insert 1 to be enclosed is placed in the first mold half 2 ( Fig. 11 ).

With the help of vacuum and / or slides 4, the space behind the undercut of the insert 1 necessary for the form fit is filled with plastic ( Fig. 12 ). The excess material is cut off behind the undercut by cutting edges introduced into the tool ( Fig. 13 ). As in Fig. 13 , also be included in the slide 4. Fig. 14 shows the finished component, with the excess plastic, below the undercut and the slide 4, separated.

A high pressure container according to the invention is shown in Fig. 15 shown. The high-pressure container comprises a cylinder 10 as a central part, the cylinder 10 consisting of a multilayer composite plastic 11 which comprises a barrier layer 12, the high-pressure container further comprising at least one half-shell 13 at one axial end of the cylinder 10, the half-shell 13 being made from a multilayer composite -Plastic 11 which comprises a barrier layer 12, wherein the half-shell 13 further comprises an essentially rotationally symmetrical insert part 1, namely a boss part, the insert part 1 comprising an undercut with regard to demolding in the direction of the longitudinal center axis of the insert part 1, the multilayer composite Plastic 11 of the half-shell 13 is arranged axially on both sides of the undercut of the insert 1.

The undercut is formed by a foot part 14 at the end of the insert 1 facing the inside of the container, which has a larger diameter than a central part of the insert 1. The multilayer composite plastic 11 is arranged axially on both sides of the foot part 14.

The foot part 14 has several grooves 15 which are filled with the multilayer composite plastic 11 of the half-shell 13.

The insert 1 essentially has the shape of a hollow cylinder. The foot part 14 essentially has the shape of a hollow cone.

A groove 15 filled with the multilayer composite plastic 11 of the half-shell 13 runs around an inner circumference of the foot part 14.

The multilayer composite plastic 11 of the cylinder 10 merges into the multilayer composite plastic 11 of the half-shell 13.

The multi-layer composite plastic 11 of the half-shell 13 and also of the cylinder 10 comprises a layer made of HDPE as the outermost layer and a barrier layer 12 made of EVOH. The HDPE can be in the form of HDPE-S (black), after which a regranulate layer can be arranged, an adhesion promoter, the EVOH layer, optionally again an adhesion promoter and optionally also as the innermost layer again an HDPE layer.

The high-pressure container comprises two half-shells 13 at the axial ends of the cylinder 10, both half-shells 13 being designed as described above, i.e. having a boss part 1 that is embedded in the multi-layer composite plastic 11.

The cylinder 10 and the two half-shells 13 are wrapped with a fiber material 16, preferably with a composite material comprising carbon fibers and / or glass fibers and / or epoxy resin.

Overall, a high-pressure container is thus specified which can be used to store gases under high pressure. This is made of lightweight construction and has a multi-part, multi-layer plastic liner, consisting of two dome caps 13 and a cylinder 10, which ensures gas tightness and contains a permeation barrier 12.

In the two dome caps 13, boss parts 1, namely a “headstock” and a “tailstock” are integrated.

The permeation properties are provided by a barrier layer or barrier layer 12 contained in the layer structure of the liner both in the dome caps 13 and in the cylinder tube 10.

The high-pressure container gets its mechanical strength from a fiber-reinforced composite 16, which is applied to the plastic liner in the winding process and then cured.

List of reference symbols

1

Insert part, boss part

2

first mold half

3

first plastic plate

4th

Slider

5

second mold half

6th

second plastic plate

7th

recording

10

cylinder

11

Multi-layer composite plastic

12th

Barrier layer

13th

Half shell

14th

Foot part

15th

Groove

16

Fiber material

Claims (8)

High-pressure container comprising a cylinder (10) as a central part, the cylinder (10) consisting of a multilayer composite plastic (11) which comprises a barrier layer (12), the high-pressure container furthermore having at least one half-shell (13) at one axial end of the cylinder ( 10), wherein the half-shell (13) consists of a multilayer composite plastic (11) which comprises a barrier layer (12), the half-shell (13) further comprising an essentially rotationally symmetrical insert part (1), namely a boss part, wherein the insert (1) comprises an undercut with respect to a demolding in the direction of the longitudinal center axis of the insert (1), the multi-layer composite plastic (11) of the half-shell (13) being arranged axially on both sides of the undercut of the insert (1). High pressure container according to claim 1,
characterized in that the undercut is formed by a foot part (14) at the end of the insert (1) facing the inside of the container, which has a larger diameter than a central part of the insert (1). High pressure container according to claim 2,
characterized in that the foot part (14) has at least one groove (15) which is filled with the multi-layer composite plastic (11) of the half-shell (13), preferably several grooves (15). High pressure container according to claim 2 or 3,
characterized in that the foot part (14) essentially forms a hollow cone or hollow cylinder and preferably runs around at least one groove (15) filled with the multi-layer composite plastic (11) of the half-shell (13) on an inner circumference of the foot part (14). High pressure container according to at least one of the preceding claims,
characterized in that the multi-layer composite plastic (11) of the cylinder (10) merges into the multi-layer composite plastic (11) of the half-shell (13). High pressure container according to at least one of the preceding claims,
characterized in that the multi-layer composite plastic (11) of the half-shell (13) comprises at least one layer made of HDPE and a barrier layer (12), in particular EVOH, preferably also a regranulate and / or a second HDPE layer and / or at least one adhesion promoter layer includes. High pressure container according to at least one of the preceding claims,
characterized in that the high-pressure container comprises two half-shells (13) at the axial ends of the cylinder (10), both half-shells (13) preferably being designed as described in at least one of the preceding claims. High pressure container according to at least one of the preceding claims,
characterized in that the cylinder (10) and the two half-shells (13) are wrapped with a fiber material (16), preferably with a composite material comprising carbon fibers and / or glass fibers and / or epoxy resin.

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